classic hacks

If you want to learn Morse code and you don’t have a teacher, you’d probably just head over to a website or download a phone app. Before that, you probably bought a cassette tape or a phonograph record. But how did you learn Morse if you didn’t have any of that and didn’t know anyone who could send you practice? Sure, you could listen to the radio, but in 1939 that might be difficult, especially to find people sending slow enough for you to copy.

Wireless World for August 3rd, 1939, has the answer in an article by [A. R. Knipe] on page 109. While you probably wouldn’t use it today, it is a great example of how ingenious you can be when you don’t have an Arduino and all the other accoutrements we take for granted today.

It’s a common situation faced by every hard-working American – you get home after a long day at the calcium mines, and find yourself stuck with a pile of colored golf balls that simply aren’t going to sort themselves. Finally, you can put away your sorting funnels and ball-handling gloves – [Anthony] has the solution.

That’s right – it’s a delta robot, tasked with the job of sorting golf balls by color. A Pixy2 object tracking camera is used to survey the table, with the delta arms twitching around to allow the camera to get an unobstructed view. Once the position of the balls is known, a bubble sort is run and the balls rearranged into their correct color order.

[Anthony] readily admits the bubble sort is very inefficient at this task; it was an intentional choice so it could be later compared with other sorting methods. [Anthony] also goes into detail, sharing the development process of the suction gripper as well as discussing damping methods to reduce noise.

Floppy drives have particularly low-level interfaces, offering up little more than a few signals to indicate the position of the head on the disk, and pulses to indicate changes in magnetic flux. The data is encoded in the pattern of flux changes. This has important implications as far as preservation goes – it’s best to record the flux changes themselves, and create an image of the exact magnetic state of the disk, and then process that later, rather than trying to decode the disk at the time of reading and backing up just the data itself. This gives the best likelihood of decoding the disk and preserving an accurate image of floppy formats as they existed in the real world. It’s also largely platform agnostic – you can record the flux changes, then figure out the format later.

[CHZ-Soft] takes this approach, explaining how to use a Saleae logic analyser and a serial port to control a floppy drive and read out the flux changes on the disk. It’s all controlled automatically through a Python script, which automates the process and stores the results in the Supercard Pro file format, which is supported by a variety of software. This method takes about 14MB to store the magnetic image of a 720KB disk, and can even reveal a fingerprint of the drive used to write the disk, based on factors such as jitter and timing.

While trying to revive a Donkey Kong Jr arcade board, [Jelmer Bruijn] found himself in the market for an EPROM programmer and became the proud owner of a 1990’s era Dataman S4. Despite its age, it’s a fairly nice tool which allows you to read and write a laundry list of different EPROM types, all without being tied to a computer. The only catch is that a few types of chips need an adapter to work in the Dataman S4, some of which are unsurprisingly no longer available.

After some above and beyond support from the current crew at Dataman set him on the right track, [Jelmer] decided to try his hand at reverse engineering how the old adapters worked so he could build his own. His ultimate goal was to read 40 pin EPROMs on the 32 pin Dataman S4, but in the end he says the information he gathered should be applicable for building other adapters if you ever find yourself in need of such things.

As you might expect, there’s a bit more to the project than a simple pin adapter. [Jelmer] assumed some kind of shift register or latching arrangement would be required to make up for the shortage of pins on the Dataman S4’s ZIF socket. It was just a matter of figuring out how it all went together.

Luckily, [Jelmer] found that the programmer would happily attempt to perform operations on a 16 bit EPROM even though no adapter was physically present. This gave him a chance to probe around with a logic analyzer to figure out what it was trying to accomplish. The trick turned out to be splitting the 16 bit bus into two 8 bit buses which are requested sequentially.

With careful observation, close studying of 16 bit chip datasheets, and much brow furrowing, he was eventually able to come up a design that used five 74xx573 latches and put a schematic together in Eagle. There were a few kinks to iron out when the boards finally arrived, but ultimately the design worked on the first try. [Jelmer] says the same technique should work for 42 pin EPROMs, but as Dataman still actually sell adapters for those he decided not to supply schematics for it.

If you imagine somebody playing chess against the computer, you’ll likely be visualizing them staring at their monitor in deep thought, mouse in hand, ready to drag their digital pawn into play. That might be accurate for the folks who dabble in the occasional match during their break, but for the real chess aficionados nothing beats playing on a real board with real pieces. Of course, the tricky part is explaining the whole corporeal thing to a piece of software on your computer.

The pocket sized chess computer uses a “sandwich” style construction which shows off the internals while still keeping things reasonably protected. All of the electronics are housed on the center custom PCB which features a HT16K33 driver for the dual LTP-3784E “starburst” LED displays, a MCP1642B voltage regulator, 16 TL3305 tactile switches for the keyboard, and a MCP73871 battery management chip for the 3.7 volt lithium-ion battery that powers the whole show. The Pi Zero itself connects to the board by way of the GPIO header, and is mechanically supported by the standoffs used to hold the device together.

On the software side of things, the Pi is running the mature Stockfish open source chess engine. In development now for over a decade, this GPL licensed package aims to deliver a world-class chess gameplay on everything from smartphones to desktop computers, and we’ve seen it pop up in a number of projects over the years. [slash/byte] has provided a ready to flash SD card image for the Raspberry Pi, and even provides detailed installation and setup instructions which guide you through some of the more thorny aspects of the setup such as getting the Pi running from a read-only operating system so that abrupt power cuts don’t clobber the filesystem.

Over the years, some of the most impressive projects we’ve seen revolved around playing chess, and this latest entry by [slash/byte] is no exception. Another example of the lengths the chess community will go to perfect the Game of Kings.

XInput is an API that is used by applications to interface with the Xbox 360 Controller for Windows. The 360 controller became somewhat of a “standard” PC gamepad, and thus many games and applications support the XInput standard.

The controller in question is the JJRC Q35-01, a trigger-type RC controller available for under $20. The conversion is executed neatly, with the original STM microcontroller being removed from the board, and the PCB traces instead being connected to a Teensy 3.5 which takes over running the show.

The conversion is remarkably complete, with the team not stopping at just reading the buttons and steering potentiometer. A USB logic analyzer was used to figure out how to control the LCD, and a calibration mode implemented just in case.

Lightsabers have enchanted audiences since their appearance in the very first Star Wars film in 1977. Unfortunately, George Lucas hasn’t shared the technology in the years since then with the broader public, so we’re left to subsist on pale imitations. This is just such a build.

The closest human analog to Jedi technology is the laser, and this build uses 8 of them in combination with two LEDs. They’re aimed to coincide at a fixed distance above the hilt. A CO2 bicycle inflater is then used to blow through an e-cigarette to create a fog. This makes the red lasers readily visible to the human eye.

This ersatz lightsaber does have its limitations – fast motion tends to scatter the fog, making it once again invisible, and it’s really at its best held in a vertical orientation. There’s also some divergence beyond the focused point. With that said, it does look somewhat impressive when held still, smouldering away.